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    <meta charset="UTF-8">
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    <title>Document</title>
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<body>
    <script>
        function Person(){
            this.name = 'jack'
            this.age = 18
        }
        Person.prototype.say = function(){
            console.log('say');
        }
        Person.prototype.type = 'k'

        let p1 =new Person()
        console.log(p1.hasOwnProperty('type'));
    </script>
</body>
</html>